Ecotype

ecotype

[′ek·ə‚tīp]

(ecology)

A subunit, race, or variety of a plant ecospecies that is restricted to one habitat; equivalent to a taxonomic subspecies.

Ecotype

a group of similar populations within one and the same plant species that are adapted to certain climatic, edaphic, or cenotic conditions and that have developed, under these conditions, hereditary morphological, physiological, biochemical, and other features. Thus, an ecotype is isolated with respect to distribution; genotypically it is an intraspecific subdivision, which distinguishes it from a biotype.

The term “ecotype” was introduced in the 1920’s by the Swedish scientist G. Turesson. Different plants have different numbers of ecotypes. The ecotypic composition of a species becomes more varied as its geographic range and ecological amplitude increase. For example, 36 ecotypes have been distinguished in the pine Pinus silvestris and 27 in the spruce Picea abies. Ecotypic polymorphism is most clearly manifested at the center of speciation and morphogenesis. In the medic Medicago falcata, for example, there are many ecotypes in the Caucasus and only a few in the northern USSR. Parallel ecotypic differentiation is observed in many species. Thus, the wormwood Artemisia campestris, sheep sorrel (Rumex acetosella), and Silene uniflora, which grow in bright, dry habitats where there are strong winds, develop eco-types with procumbent stems.

Three main groups of ecotypes are distinguished: climatic, edaphic, and biotypic. Climatic, or geographic, ecotypes occupy a separate part of the area of distribution of a species and originated under the influence of specific climatic conditions; for example, in the awnless brome (Bromus inermis), the southern eco-type differs from the northern one by its nanism, narrow rough leaves, and wax coating. Edaphic ecotypes develop under the influence of soil and ground conditions, such as the pine ecotype on the chalky outcrops of the Don River, which has even been described as the independent species Pinus cretácea. Biotypic, or cenotic, ecotypes appear and develop mainly under the influence of plants together with which the given species form plant communities, for example, the field and forest ecotypes of the cocksfoot (Dactylis glomerata) and the forest and dune ecotypes of the narrow-leaved hawkweed (Hieracium umbellatum).

The development of an ecotype is a lengthy process. If an ecotype has progressive characteristics, which permit it to extend the range of the species, it may give rise to a new species, and consequently an ecotype is one of the stages in the process of specia-tion.

An evaluation of variability in the expression of forage characteristics of interest and of the genetic diversity of ecotypes and hybrids of different species of the genus Paspalum by means of a meta-analysis enables the comparison of data from different trials, thus increasing the number of ecotypes, hybrids, and repetitions evaluated.

Species composition and quantity of the pooled samples of different mowing regimes (LF: life form; EF: ecotype form; M: mowing once a year in May; MS: mowing twice a year in May and September; S: mowing once a year in September; C: abandoned without management; arbu: arbusticol; gra: graminicol; pra: pratinicol; sil: silvicol; hyg: hygrophilic; mes: mesophilic; m-hyg: moderately-hygrophilic; m-ther: moderately-thermophilic; ther: thermophilic).

We recommend reducing block size from 250 x 250 m to 200 * 200 m in the future for two reasons: (1) to avoid inaccuracies in ecotype assignment and (2) to space line transects within the block closer together.

In plants subjected to 100% FC, the TLA was higher in seedlings from Laranjeira and lower in the seedlings of BRS-Para; under 130% FC, the TLA was higher in seedlings from Laranjeira and the ecotype Hideo (Table 1).

The differentiation of California coastal ecotype bottlenose dolphins from the offshore ecotype has successfully relied on the multiple data types and sources, including analyses of morphology, microbiology and genetics, as well as photo-identification (Walker 1981; Perrin et al.

Meanwhile, a western mountain ecotype became the source of upland ecotypes that migrated to the arid and semiarid Great Plains, which then became a secondary--not the primary--center of switchgrass diversity.

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